Return to Revisions

#Java, 85 bytes

This is surprisingly short in Java.

void a(int a){String b="";for(int c=0;c++<a;System.out.println(b))b+=(c>1?" ":"")+c;}

Indented:

void a(int a){
    String b="";
    for(int c=0;c++<a;System.out.println(b))
        b+=(c>1?" ":"")+c;
}